Apparatus for maintaining uniform pressure in driers.



No. 858,089; PATENTED JUNE 25, 1907. w. B. MASON.

APPARATUS FOR MAINTAINING UNIFORM PRESSURE IN DRIERS.

APPLICATION FILED MAY 17. 190s.

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UNITED STATES PATENT oEEIcE.

WILLIAM B. MASON, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO THE MASONREGULATOR COMPANY, OF SAOO, MAINE, A CORPORATION OF MAINE.

No. 858,089. v

Specification of Letters Patent.

Patented June 25, 1907.

Application filed May 17,1906. Serial No. 317,329,

stance, as the chamber of a paper drier, al-v though the main source ofsupply for the pressure is variable, the other or auxiliary source ofsupply being at a pressure relatively higher than the main source ofsupply.

This invention is adapted particularly for use where it is desired tomaintain a constant pressure in a chamber which is supplied with steamfrom the exhaust pipe of a steam engine, additional pressure beingobtained when necessary from the boiler.

My present invention is also especially adapted for use in connectionwith small steam pipes which can be readily carried to any convenientpoint so that the various pieces of mechanism which embody my inventionmay be conveniently grouped upon a single panel or board.

The invention furnishes a simple and compact mechanism and aflords athoroughly re liable means for accomplishing the result desired, namely,the maintenance of a substantially constant pressure in the chamber. Itis also exceedingly economical in steam because it utilizes the exhauststeam to the fullest extent possible.

The invention will be fully understood from the following specificationtaken in connection with the accompanying drawings, and the novelfeatures thereof are pointed out and clearly defined in the claims attheIn the drawings,the figure. is a diagrammatic view of the mechanismembodying my invention.

Referring to the drawings, atAis indicated the variable source of steamsupply, as, for

instance, the exhaust pipe from the engine. The exhaust pipe A isconnected by the small pipes B with the paper driers or other chambersin which it is desired that constant pressure be maintained. At C isindicated a vent to the atmosphere connectedto the exhaust pipe A andcontrolled by the vent valve D I which is mounted upon the panel orboard E. The exhaust pipe A is also connected with a boiler pipe Sthrough which the steam or other fluid under high pressure is admittedto the chamber when required. The flow through this pipe is controlledby the high pressure valve F also mounted upon the panel E.

At G there is shown a pressure weighing device connected by the pipe Hwith the chamber supply pipe and movable in re sponse to changes inpressure in the said chamber. This pressure weighing device may be ofany suitable form, but in practice I find it convenient to use thedevice shown and described in Letters Patent N 0. 561,600, granted to meJuly 9, 1896. The said pressure weighing device G is connected as shownat R to a source of water supply under pressure, such, for instance, asa city water main, and operates when the pressure in the chamber risesabove a predetermined point to cause the wheel J to rotate and to windthe chain or flexible connection K upon it. The said chain K passes overvarious pulleys L, and is attached to one end of a lever M pivoted at Oto the panel E. The chain or flexible connection K is furnished with aheavy counterweight N which serves to keep it taut when it is unwoundfrom the pulley J.

When the exhaust pipe A is furnishing too much steam or steam at toohigh a pressure to the chamber, itis necessary to open the vent valve Dto allow a portion of the steam to escape to the atmosphere, and tolower the pressure in the chamber thereby. On the other hand, if thesteam furnished by the exhaust pipe A is insufiicient to maintain thedesired pressure in the chamber, it is necessary to open the highpressure valve F and allow steam from the boiler or other source of highpressure to flow into the into the drying chamber.

thus causing the left hand end of the said lever M to be correspondinglydepressed. The left hand end of the lever M is connected bymeans of apivoted connecting rod 11 with the high pressure valve lever 12, thesaid pivoted rod 11 being screw threaded and provided with a movabletappet 13 which is adjustable vertically on the said pivoted connectingrod 11. The high pressure valve lever 12 is pivoted at 131 to a movablefulcrum 14 fixed to the casing of the valve F, and is guided in a slotin a fixed arm 141, also supported on the said casing of the valve F.The valve spindle 16 is pivotally connected to the said valve lever 12between the fulcrum and the fixed arm 141, so that the said valveis'closed by the downward movement of the high pressure valve lever 12and opened by its upward movement.

The vent valve D is similarly provided with a valve lever 16 connectedby a second pivoted connecting rod 17 with the operating lever M, saidpivoted connecting rod also being furnished with an adjustable tappet18.

The vent valve lever 16 is pivoted to a movable fulcrum 19, which isnearer the point of the a plication of the lever than is the valve s inle 20 which is operated thereby. A s otted guiding arm 21 is alsoprovided. Both valve levers 12 and 16 are provided with counterweights22 and 23 which are adjustable longitudinally of the said valve levers,and which tend to keep the said levers in contact with the tappets.

When the right hand end of the main operating lever M has been raised bythe rise in pressure of the chamber above the predetermined point, itallows the high pressure valve lever 12 to fall and thus closes the highpressure valve F, thereby preventing the further admission of highressure steam W hen the valve lever 12 moves downwardly far'enough toclose the valve F, it engages the bottom of the slot in the arm 141fixed to the casing of the valve F which prevents the valve lever 12from moving further, but allows the connecting rod 11 by reason of theloose con nection between it and the valve lever to continue itsmovement irrespective of the valve lever 12, the valve F remainingclosed until the ta pet 13 is brought in contact again with t e underside of the valve lever 12, as will be hereinafter described. If closingthe supply of high pressure steam from the source of supply is stillinsufficient to cause the pressure in the drier or chamber to fall tothe desired point, or to put the matter in a diiferent way, if the steamfrom the exhaust pipe A is more than suiiicient to maintain thepredetermined pressure in the chamber, the right hand end of the lever Mcontinues its u ward movement, causing the left hand. end thereof to bedepressed and the tappet 18 thereon to contact with the lever 16, thusdepressing the said vent valve lever and opening the vent valve D toreduce the ressure in the chamber as is necessary.

hen the pressure in the chamber falls, the reverse action takes place.The pressure weighing device allows the counterweight N to unwind thechain or flexible connection K from the wheel J and to depress the righthand end of the lever M, thus allowing the vent valve to rise until theend upon which its weight 23 is located comes in contactwith the bottomof its slot. If this change is not su'llicient to raise the pressure inthe chamber to the required amount, the movement of the lever Mcontinues, the tappet 13 comes in contact with the high pressure valvelever 12 and the high pressure valve F is again opened to admit steam inthe chamber.

Under ordinary conditions, I find that the steam from the exhaust pipeis suflicient to maintain the desired pressure in the chamber and solong as this is the case, it is only necessary for the vent valve to beopened and closed as required to reduce the pressure in the chamber tomaintain the predetermined pressure at a practically constant point inthe chamber. If, for any reason, the exhaust pipe should fail to supplythe requisite amount of steam, the device will then open the highpressure valve, as has been previously described. At other times, thehigh pressure valve remains inactive.

While I have described my present invention as applied to a chambersupplied with steam from the exhaust pipe of an engine, and having anauxiliary supply from a boiler, it will be understood that my device isequally applicable to any place where it is desired to maintain aconstant pressure from a source of supply which is variable assisted byan auxiliary supply at a high pressure.

I claim as my invention:

1. Controlling mechanism for maintaining a predetermined pressure in achamber supplied from two sources, the main source of which is variable,and the auxiliary source of which is of relatively high pressure, whichcomprises a vent valve and a high pressure valve, a main operatinglever, whose movement in one direction acts to close the high pressurevalve and open the vent valve and whose movement in the other directionacts to close the vent valve and open the high pressure supply valve,and a pressure weighing device responsive to changes in pressure in thechamber and operating to move th said lever.

2. Controlling mechanism for maintaining a predetermined pressure in achamber supplied from two sources, the main source of which is variable,the auxiliary source of which is of relatively high pressure, whichcomprises a vent valve, a high pressure valve, a main operating lever,connections 0 between the main operating lever and the said two valves,and a pressure weighing device responsive to changes in pressure in thechamber, and operating to move the said main operating lever in onedirection to close the vent valve and open the high pressure valve andin the other direction to close the high pressure valve and open thevent valve.

3. Controlling mechanism for maintaining a predetermined pressure in achamber supplied from two sources, the main source of which is variable,the auxiliary source of which is of relatively high pressure, whichcomprises a vent valve and a valve lever therefor, a high pressure valveand valve lever therefor, a main operating lever, connections betweenthe main operating lever and the said two valve levers, and a pressureweighing device responsive to changes in pressure in the chamber andoperating to move the said main operating lever in one direction toclose the vent valve and open the high pressure valve and in the otherdirection to close the high pressure valve and open the vent valve. a

4. Controlling mechanism for maintaining a predetermined pressure in achamber supplied from two sources, the main source of which is variable,and the auxiliary source of which is of relatively high pressure, whichcomprises a vent valve and a valve lever therefor, a high pressure valveand a lever therefor, rests for the said valve levers when the valvesare closed, a main operating lever, intermediate connections between thesaid main operating lever and the said valve levers, tappets on the saidintermediate con= nections alternately contacting with the said valvelevers, and a pressure weighing device responsive to changes in pressurein the chamber and operating to move the said main operating lever inone direction to close the vent valve and open the high pressure valve,and in the other direction to close the high pressure valve and open thevent valve.

In testimony whereof I afliX my signature, in presence of two witnesses.

WILLIAM B. MASON.

WVitnesses:

GEORGE PQDIKE, J. HENRY PARKER.

